In various substrate-processing apparatus, substrates are conveyed while being in physical contact with each conveying system. In case where a substrate being conveyed or the conveying systems have particles adherent thereto, the succeeding substrates are contaminated one after another. It has hence been necessary to periodically stop and clean the apparatus. Because of this, there has been a problem that the cleaning operation results in a reduced time efficiency and necessitates much labor. In order to eliminate such problems, a technique for removing particles adherent to inner parts of a substrate-processing apparatus by conveying a substrate having a pressure-sensitive adhesive substance bonded thereto (e.g., Japanese Patent Laid-Open No. 154686/1998) and a technique for removing particles adherent to the back side of substrates by conveying a platy member (Japanese Patent Laid-Open No. 87458/1999) have been proposed.
The technique for removing particles adherent to inner parts of a substrate-processing apparatus by conveying a substrate having a pressure-sensitive adhesive substance bonded thereto is an effective method for eliminating the problem described above. However, there is a possibility in this technique that the pressure-sensitive adhesive substance might adhere too tenaciously to a contact part of the apparatus to be separated therefrom. Namely, this technique has a possibility that the substrate cannot be conveyed without fail or might damage the conveying device. This problem is severe especially in apparatus having a chuck table employing a vacuum holding mechanism.
In the case where a pressure-sensitive adhesive substance is used as a cleaning layer, the surface of the pressure-sensitive adhesive substance is generally protected with a release film coated with a release agent such as a silicone. However, the technique described above has a problem that components of the release agent migrate/transfer to the surface of the cleaning layer and the release agent components which have migrated contaminate the substrate contact part of the conveying device.
Furthermore, the technique for removing particles by conveying a platy member has a problem that it is inferior in dust-removing ability, which is important, although conveyance can be conducted without arousing any trouble.
In view of such circumstances, an aim of the invention is to provide cleaning sheets and a transfer member having a cleaning function which each can be conveyed into a substrate-processing apparatus without fail and with which particles adherent to inner parts of the apparatus can be easily removed without fail.